Electricity generation coupled with hydrogen production at room temperature by lignin-derived aldehyde flow fuel cell based on Ag-CuxO/CF electrocatalyst

Hydrogen production by biomass electrolysis offers a promising and sustainable route for producing green hydrogen and high-value utilization of biomass. However, this process consumes electricity and suffers from low anode Faraday efficiency of the organic electro-oxidation reaction. Herein, we develop a novel strategy that integrates a room-temperature, high-power lignin-derived aldehyde flow fuel cell (FFC) with hydrogen production, which converts the power-consuming electrocatalytic hydrogen production step into an electricity-generating process. The highly active Ag-Cu x O/CF (copper foam) electrocatalyst exhibits dual functionality of efficient electricity generation and simultaneous hydrogen production by catalyzing low-potential aldehyde group oxidation at the anode, which concurrently releases electrons and generates hydrogen. The Ag-Cu x O/CF electrocatalyst can significantly improve the electron transfer rate and catalytic conversion efficiency of the anode, attributable to its mixed Cu 0 /Cu + valence states, enlarged double-layer capacitance (C dl ), reduced interfacial resistance, and optimized adsorption capacity. The Ag-Cu x O/CF catalyst achieves ∼95 % benzaldehyde conversion and ∼98.4 % Faradaic efficiency for hydrogen production at 0.35 V RHE . Furthermore, the FFC based on Ag-Cu x O/CF electrocatalyst demonstrated excellent dual-functionality at room temperature, achieving both a power density of 173.5 mW cm −2 and a hydrogen production rate of 1.96 mmol cm −2 h −1 . The constructed FFC achieved a room-temperature power density threefold greater than the reported lignin-based power generation technology, while maintaining comparable hydrogen production rate to biomass electrolysis processes. This study provides a novel approach to reduce the cost of green hydrogen production and mitigate the global energy crisis.